Compressor



June 1941- w. w. WISHART 2,246,278

' COMPRESSOR Filed July 9, 1936 2 Sh eets-Sheet 1 ll 8 un! I v -55 I 21/ 1M w art @:M WW

J ne .17, 1941.

w. w. wrsHA-R COMPRESSOR Filed July 9, 1936 v2 Sheets-Sheet 2 means incorporated therein PatentedfJune 17, 1941 U'NlTED STATES PATENT OFFICE William W.

Wlshart, Chicago, Ill., Davidson Manufacturing Corporation,

ass ignor to Chicago,

111., a corporation of Illinois Application July 9, 1936, Serial No. 89,703 10 Claims. (Cl. 230-440) My invention relates in general to fluid pressure devices and has more particular reference to a rotary apparatus more particularly adapted for use in high compression of fluidmedia and adapted also for producing high vacuum conditions, the invention including novel features having general application in fluid or hydraulic apparatus. The present application comprises a continuation in part of my co-pending application Serial No. 743,196, filed September 8, 1934, for Compressor.

pressure time, provides adequate sealing at the junction of the side edges of the blade with the end plates.

' -of the cylinder.

An important object of the invention is to pro-- device having improved for sealing the devide a fluid pressure vice against fluid leakage.

Another important object is to pump for developing pressure in a medium .including means pump for utilizing the pressure developed in the work medium to assist in sealing the pump.

Another important object is to provide an flow device having facilities for lubricating the operating parts of the device including an arrangement whereby the medium used to lubricate the" parts is applied under pressure to seal the device against fluid leakage therein.

Another important object is to seal a device of the character described by applying at places where leakage is likely a sealing medium under pressuredn excess of the maximum fluid pressures developed by the device when in operation.

Another important object is to provide a rotary pump particularly well adapted for use in compressing a gaseous work medium such as air, ammonia gas, and the like, but suitable, of course, for pressure and vacuum pumping purposes generally, said pump comprising a cylinder provide a fluid work and cooperatively associated and relatively movabe to provide the fluid forcing,-evacuating or compressing function upon fluid delivered in said work chamber, one of said elements carrying a. blade having bearing relationship on the other to form a driving connection therebetween.

Another important object is to provide .a rotary fluid pressure device comprising a cylinder and a'relatively eccentric piston wherein the cylinder comprises an annular rim, carrying an inwardly extending radial projection or blade, the opposite sides of the rim carrying end plates secured thereto in position clampingly engaging the opposite side edges of said blade, whereby to afford a structure which can be readily fabricated and assembled and which, at the same incorporated in the passed to the piston,

A further object is to mount the piston within the cylinder on an eccentric portion of-a shaft,

which also has a portion or shank extending out through a side wall of the cylinder and to form the channel, through which the work material is as a longitudinal passage formed in the said shaft. A further object is to form a duct connecting with the work space and including a portion extending substantially radially in an end wall of the cylinder.

A still further object is to provide a resilient seal between the communicating ends of a chan- .nel in which through thepiston and the radial duct cylinder wall.

Another object is to provide means to adjust the eccentricity of the piston axis with respect to the axis of the cylinder by angularly adlusting the pistonecarrying shaft. in its support so as to adjust the position of the eccentric piston-carrying portion of the cylinder.

Another important object is to form the cylinder with an axle at one end'and an opening at the other providing a thrust bearing, the cylinder being mounted in a casing formed with a bearing for said axle and with a thrust hearing for directly supporting the other end of the cylinder so that the fluid under pressure delivered in the housing may act upon the'cylinder to force it axially against the thrust bearing and thus assist in sealing the cylinder to the frame around the end opening in the of the cylinder; a further object being to provide the housing with a projection formingv a sleeve extending centrally of said thrust bearing and through the opening in the end wall of the cylinder and to mount; the piston-carrying shaft in said sleeve.

Another important as a hollow element or shell having an internal chamber or chambers and to provide for delivering a lubricant, under pressure, to said chambers as the piston rotates on its eccentric shaft within the cylinder, said piston being formed with openings communicating said chambers with the inner faces of the cylinder end plates.

Another object is to provide a. device of the character mentioned and having a lubricating system designed to afiord improved sealing against passage of 'the working fluid between the contact 'end surfaces of the piston and the end the work medium is conducted shaft Within the object is to form the piston vention.

I along the line 33 in sealing and lubricating function and to provide a circulating lubricant system for receiving the used lubricant and returning'it under increased pressure to the chambers of the piston; a further object being to cool the sealing and lubricating. .medium prior to delivery under pressure to the device.

Another object is to provide a duct connected with the work space and including a portion extending longitudinally in the cylinder shaft; a

further object being to provide a sealed chamber about the shaft communicating with said duct.

Still another object is to provide apparatus adapted to produce unusually high pressures in a single stage, actual apparatus embodying the invention having been operated, regularly and con-- tinuously to compress air at pressures substantially in excess of four hundred pounds per square inch, the single stage device further being Operable to produce a vacuum of 99.95%, that is to say, a

vacuum of 29.05 millimeters with a barometer of 29.0625 millimeters.

These and other numerous objects, advantages, and inherent functions of the invention'will be apparent from the following description, which,

taken in connection with the accompanm'ng drawings, discloses a preferred embodiment of my in- Referring to the drawings: v

Figure 1 is a. diagrammatic view of a fluid forcing device embodying my present invention,

including a system for lubricating and sealing the 7 device;

Figure 2 isa diagrammatic view showing amodified arrangement of the lubricating and sealing system;

Figure 3 is a sectional view taken substantially Figure 1;

Figure .4 is a fragmentary view of apart of the device; r l

Figure 5 is a sectional view taken substantially along the line 5-5 in Figure 4;

Figure 6 is a. sectional view taken substantially along the line 6-6 in Figure-3;

Figure 7 is a sectional view showing a modified arrangement of a portion of the device;

Figures 8, 9, 10 and 11 are perspective views of parts of the device; and

Figures 12 and 13 are modified arrangements of the device.

To illustrate my invention, I have shown on the drawings an hydraulic apparatus comprising a rotary machine especially well adapted to function as a compressor for gaseous media and adapted also to operate as a pump for fluid forcing or evacuating purposes, although it will be obvious that certain features of the invention may have general application in any type of hydraulic or fluid flow apparatus.

Apparatus embodying my invention, however, is characterized by the provision of means for sealing the same in order to provide unusually high efliciency of operation so that where used as a vacuum or fluid forcingpump or compressor,

devices embodying my present invention will develop heavy pressures in the work medium or exceedingly high vacuum conditions, as the case may be, and, at thesame time, will operate at great efllciency so that the invention will have great utility more particularly where the work medium isof gaseous character.

To provide the foregoing characteristics, I

utilize certain novel structural arrangements whereby the operating parts of the units are sealed effectively against the escape of the working medium, said sealing means including not only the particular form of parts employed but also the cooperation of said parts with each other and with the compressed ,work medium, as well as the provision of an improved lubricating method and system whereby the operating parts ably both mounted for rotation about relatively eccentric parallel axes, with the piston in' contact with the ,inner surface of the cylinder and, since the inner diameter of the cylinder is larger than the diameter of the piston, a crescent shaped working space I 5 is defined therebetween.

The frameor casing H provides a closed housing, in which'the elements H and I3 are mounted and the work medium is delivered into the work chamber preferably through a channel 5| extending axially through the piston and thence radially through a duct 49, which is formed in the cylinder walls. The casing I4 may be of any suitable form, but I prefer toform the same as a pair of cooperating parts, one of which is formed with a base It, and upstanding walls, including an end wall l8 and preferably cylindrical side walls 22 forming with the end wall a preferably cylindrical compartment open at one end. The other casing part 24 adapted to fit upon and close the open end of the compartment defined by the walls l8 and 22. The walls 22 and 24 are preferably formed with an interfitting tongue and groove formation 26 to seal the joint therebetween andthe parts may be secured together in any desired fashion as by means of the bolts 28.

One of the cooperating parts, preferably the cylinder, is provided with means comprising an axle l1 for driving the same. The cylinder preferably carries a blade I9 extending in a sub stantially radial slot 20 formed inthe piston so that rotation of the cylinder by means of the shaft will cause rotation of the piston through comprises a p eferably circular plate,

side of the blade l9, opposite from *annular boss portion 31. The bearing l9 will be drawn into the work space l and eventually delivered on the side of the blade opposite from the inlet. The medium may be expelled through a suitable "exhaust opening 34, on the port. While I have s own my present invention as applied in a rotary compressor or pump, in

' which both the cylinder and the piston are roto pump the work medium from the inlet port 32 to the outlet 34, it will be obvious that many features of the invention may be applied in similar arrangements, in which one of the cooperating fluid-forcing elements is stationary, while the other rotates about an axis eccentric with respect to the axis of the stationary member to thus accomplish the fluid-forcing function; and I do not wish to limit my invention, necessarily, to a device in which both the piston and cylinder rotate.

I prefer, however,

tated in order to arrange the parts so that the cylinder at least rotates, and, to this end, and further to s'mplify the construction and assembly of the cylinder, I prefer to form the same as an assembled structure comprising an annular element or ring 23 on the opposite ends of which are mounted circular discs 25, forming end plates, the ring and end plates being together in any suitable fashion, as by means of a plurality of spaced apart fastening elements preferably comprising bolts 21 applied at the peripheral edges of the end into the edges of ring 23. One of the end plates 25 is fixed, on the shaft H, which is journalled in a bearing 29 formed in the frame It. This bearing is preferably of the ball or roller typ although a bushing may be utilized if desired. A shaft seal'3l of any well suited for fluid along the spring 34 to seat sealingly on the through which the shaft extends, the spring serving also to compress sealing means into the cups 32 and upon the shaft.

The other of the end plates 25'is preferably formed with an axial opening defined by an 35 and the frame i4 is provided with projecting means 31 extending within said opening 33 and affording a bearing, on which the end plate 25 may be directly journalled, suitable preferably roller bearing means 39 being interposed between the surfaces defining the channel 33 and the outer surfaces of the projecting frame means 39 may, of course, be of any suitable form, and ball or roller bearings are contemplated, although, as shown-in the illustrated embodiment, I may utilize an inner sleeve 4| slidingly supported on the projecting frame portion 31, a second sleeve 43 surrounding and slidingly fitting the sleeve 4| and slidingly fitting into the channel 33 of the end plate. A thrust bearing comprising a washer 45, with which the ends of the boss 35 and the sleeve 43 have bearing engagement, is also provided, said thrust washer, in turn, sliding upon an embossment 41 formed in the the projecting frame portion 31. The embossment 41 also furnishes bearing support for an end of the sleeve element 4|.

It will be noted that the cylinder has no journal the boss 35, through which leakage of the fluid medium occur and the thrust bearing the inlet plates and extending suitable formmay be 4 71; plied to the shaft, the seal shown being particularly the leakage of frame l4 at the base ofhaving the thrust quent loss of secured comprises a pair of annular cups 32' embracing the shaft I1 and urged oppositely thereon by a wall portions 1 washer 45, I may,

end thrust by tending as,

I cylinder, but also bearing.

the inner face of axis of the cylinder;

' of the shaft opposite conjunction with pressed medium in'the casing l4, operates to firmly seal the cylinder at the thrust bearing. The fluid medium under pressure in the casing exerts a-uniform pressure on all of the external cylinder surfaces exposed within the casing. The.

exposed area of the cylinder on the side carrying the axle I1 is larger thanthearea on the side bearing, so-that the resultant it toward the pressure on the cylinder will urge right, viewing Figure 1 of the drawings, in a direction causing the thrust washer, to be squeezed between the cylinder boss 35 and the frame embossment 41. This will firmly seal the cylinder against the passage of the compressed fluid into the cylinder through the bearing 33 with conseefficiency. 1 The sealing effect provided at the thrust bearing, of course, increases with high pressure in the casing.

It is not, inmany cases, essential to depend upon the foregoing method of utilizing the axial thrust imparted to the cylinder by the compressed medium for sealing against leakage, since the seal accomplished between the contacting end surfaces of the piston and the end plates of the cylinder will usually be suflicient, particularly where a sealing and lubricating medium is delivered under pressure faces, to seal the same against leakage of the work medium therebetween. In order to reduce the mechanical losses due to friction at the thrust of course, replace which will not only reduce to equalize the external exerted on the opposed ends of the reduce friction at the thrust a ball or roller bearing,

pressures One of the end plates 25 is formed with a radially extending duct 49 opening. at one end on the plate: {substantially at the and the shaft 2|, on which the piston is mounted, tudinal channel 5|, whichopens at the inner end theaxially opening end of the duct 49, so that when the parts are assembled, the channel 5| is in communication with the duct 49 for all relatively operating positions of the piston and cylinder. The duct 49 extends radially in the end plate and opens on the inner surface of the plate near the periphery thereof, said opening being arranged in the surface of the plate adjacent one side of the blade I! and forms an inlet opening 32, through which the work medium may be delivered to the compression space I5. I:

The channel 5| in the shaft 2| is preferably enlarged at the end of the shaft facing the axially opening end of. the duct 49, and a resilient seal is arranged in said enlarged channel portion.

This resilient seal preferably comprises a sleeve 52 fitting intothe enlarged portion of the channel and having a flange overlying the end of the shaft 2| in position to engage the face of the end plate around the axially opening end of the duct 43.

The channel 5| such as the helical spring 56, acting between an internal shoulder in the channel and the inner end of the sleeve 52 in order to yieldingly urge the sleeve against the end plate whereby to provide a seal for preventing escape of the fluid medium passing through the channel 5| and duct 49. The high pressure within the casing ll to the fluid pressure of'the combetween said contacting surthe same with V is formed with a longialso carries yielding means, i

side of said blade opposite from the inlet opening.

I prefer also to slightly relieve the inner surface of the ring 23 as at 53 opposite the outlet opening. The outlet 34 is preferably provided with a valve 36, permitting the compressed fluid medium to escape from the cylinder into the casing I4,

but preventing reverse travel of the fluid into the cylinder through the outlet 34. This valve may be of any suitable or convenient form, but I prefer to utilize a flap valve and to this end may form the outlet 34 with an outstanding annular ridge 39 by fitting a sleeve 42 snugly into the opening 34 with the end of the sleeve projecting to form the ridge. A blade of spring material 44 is anchored on the cylinder in position to normally overlie and close the open projecting end of the sleeve 42. Excessive opening movement of the resilient closure strip is prevented by a substantially rigid stop bar 46 fastened to the cylinder preferably by the same fastener 49, which holdsthe strip 44 in place.

The shaft 2|, on which the piston is supported,

tained and maintained without increasing but in fact reducing the cost of manufacture. The lock nut 51, of course, secures the shaft in its adjusted position. The frame I4 is formed with an externally threaded boss 65 through which the outer end of the shaft 2| projects from the frame, and I provide a removable cap 61 adapted to be threadingly secured to said boss ln-order to enclose the outer end of the shaft 63 to protect the projecting end of the shaft and to prevent the escape of fluid along the shaft between it and the sleeve 31.

The frame or casing I4 is preferably formed with a duct69 opening on the outer surfaces of the casing and extending to the channel inwhich the shaft 2| is supported. The shaft 2| also is provided with an opening 1|, which is elongated circumferentially of the shaft and located in position to communicate the channel 69 of the frame with the channel 5| in the shaft in all of ,the adjusted positions of the shaft. The casing I4 is also provided with an outlet communicating with the interior of the has a portion extending in and supported by the projecting frame portion 31, said projecting portion being formed with a channel for receiving the shaft so that the axis of the supported portion is eccentric with respect to the rotary axis ofthe cylinder. The-shaft is mounted so that its inner end may extend within, the cylinder in position to support the piston, while the outer end extends outwardly of the frame and is preferably threaded as at 55 to receive a nut 51 in order to lock the shaft in adjusted position. The inner end of the shaft, which lies within the cylinder, preferably comprises an eccentric portion 59 (Fig. 10), on which the piston is mounted for rotation by hearing means 5|, which may be of sleevelike character as shown although ball or roller bearings also are contemplated. The end of the*shaft 2|, which projects'outwardly of the frame, is preferably provided witha non-circular head 63 adapted for. the reception of a turning instrument whereby the "shaft may be turned in the frame portion 31 in order thus to adjust thetposition of the eccentric piston-carrying portion 59. It will be obvious that the spacement of the piston and the inner wall of the cylinder at the point of contact, therebetweenmay be accurately adjusted by turning the shaft 2|, so that the cylinder and piston support bearings need not be located with extreme accuracy, thus reducing manufacturing costs, yet the piston may be accurately adjusted with respect to the cylinder to obtain a most efllcient pumping contact therebetween, it being understood, of course, that in order for maximum emciency, the piston should contact snugly .with the inner surface of the cyinder but that the contacting pressure therebetween shouldnotbe excessive, otherwise there will beundue wear set up in the piston and cylinder bearings. The adjustment also may be v used to compensate for worn bearings and other supportparts aswellas manufacturing inaccuracies, so that pumping efficiency may be obcasing so that work medium, introduced to the compressor through the inlet channel 69, may travel thence through the communicating channels 5|, in the piston shaft, and 49, in the cylinder end plate, to the inlet port 32. The medium thus introduced through the inlet port may then be passed through the working cham- -ber I5 as a result of the relative movement of the fluid-forcing parts II and I3-and be expelled through the one-way outlet 34 into the interior through the casing outlet 13.

In Figure 6 of the drawings I have shown the form wherein the bearing 29 comprises a sleevebearing. In Figure 7 a construction embodying a roller bearing 29 is illustrated.

In Figure 6 also the medium is conducted to the work space through conduit means comprising the channel 5| in \the piston support shaft,

which channel 5| communicates with the radially extendi g duct 49 at the approximate center of theemfplate. in which said duct is formed. In this construction the duct opens inwardly on the inner face of the end plate. I may, however, as shown' in Figures 12 and 13, arrange the inlet duct as a channel II9 extending in the shaft I1 and communicating with the radial duct 49 at the approximate center of the end plate. In suchan arrangement I prefer to have the duct 49 not open upon the inner face of the end plate opposite the end of the piston-carrying shaft, which shaft also need not be channeled to form the inlet 5| but may, if desired, be channeled to provide an oil inlet duct in place of the duct II3, shown in Figure 6. a

Where the embodiment having the channel H9 is employed, I prefer to arrange an extension I-2I on the end of the sleeve-dike housing portion 39, said extension having means forming a chamber .through which the shaft I1 extends and the duct I I9 opening laterally of the shaft into said chamber. A fluid delivery pipe I23 may be connected to the chamber for delivering the fluid work medium.

In Figure 12 I have shown an arrangement particularly adapted where the fluid forcing device is used as a'suction or exhaust pump, the openings in the chamber-forming element I2| through which the shaft extends, being sealed .by one of the sealing cups 32 of the seal 3| withthe chamber I2 I being sealed by a spring pressed,

of the casing. I4 and escape thencemay be operated as pressed work medium cup-shaped element I25 applied onthe shaft outside of said chamber. During the operation of the device as a suction pump the pipe I23 will form a suction connection and the, discharge I3 may be arranged to discharge at atmospheric pressure.

In Figure 13 the chamber-forming means I2I is sealed at the opening through which the shaft extends by sealing means I21, similar to the sealing means 3|, thesealing means I21 being applied and arranged entirely within the chamber I2I. With this arrangement the fluid forcing device a compressor with the pipe I23 connected to atmosphere or similar low pressure source of the fluid work medium to be compressed and the discharge I3 forms the high pressure outlet. The structure illustrated may also operate with the duct I3 connected to an oil separator connected with the circulating system H5 in order to abstract any oil which may be discharged from the apparatus with the comthrough the outlet I3.

In order to construct a device capable of developing highcompression in the working medium, or an exhaust pump capable of developing high vacuum, it is necessary to prevent leakage of the medium from the work space I5. Leakage causing loss of compression may occur, for instance, from the working space between the sides of the piston and the end plates and thence through the pistombearing and along the shaft 2I. Leakage may also occur from the high pressure or exhaust end of the working chamber past the blade I9 to the low pressure end of the work space, such leakage occurring between the side surfaces of edges of the blade andl the contacting the cylinder end plates, or between the blade and pression' the surfaces of the cylinder and piston with which I the blade engages. In order to reduce leakage around the blade from the high pressure end of the work space directly to the low I prefer to mount the blade I 9 rigidly in the cylinder. To this end, the ring member 23 is provided with a slot I5, in-which the edge of the blade is securely fastened. Alternately, the blade may be formed as an integrally inwardly extending projection on the ring. The'blade also has a width between its opposite edges exactly equal ,to the width of the ring 23 so that when the end plates 25 are clamped together upon the ring, the opposed side edges of the blade will be firmly clamped against the facing surfaces of the end plates in order thus to prevent leakage therebetween. If desired, in order to provide a more satisfactory seal at the side edges of the blade, the same may be made slightly wider than the ring 23 and the end'plates may be grooved in order to receive the opposite edges of the blade in a fashion similar to that illustrated for the attachment of the blade in. the groove I5 of the ring. In order to firmly secure the blade in mounted position in the cylinder, the same is preferably formed with a channel I1 to snugly receive an anchoring pin. I9, which extends entirely through the blade and projects at its opposite ends from the opposite side edges of the blade. The projecting ends of the pin I9 are receivedin registeringsockets 8| formed in the Y end plates.

It will be noted that the blade is fixed with respect to the cylinder and that there is no relative movement therebetween to facilitate leakage between the edges of the blade and the cylinder portions with which they engage. The blade, however, in the construction illustrated, necespressure end,

' the piston.

fluid leakage between of the piston with the cylinder and piston, will have a'rocking and reciprocating movement inthe slotted portion of In order to seal the device against the blade and the surfaces the opposite sides of the slot 20 with semi-cylindrical depressions 83 adapted to ,receive semicylindrical bearing engagement with the opposite faces of the blade,

said bearing blocks having a length such that their opposite ends bear upon the opposing faces of the end plates 25. The entire arrangement of the bearing blocks, piston slot, and blade is such'as to provide snugly fitting slide surfaces of adequate area to seal against the escape of the working medium around the blade from the high pressure inlet side, and this effect is increased because the blade is utilized to drive'the piston in a direction such thatthe bearing element 85, which engages 'the surface of the blade facing the high pressure or exhaust end of the work chamber, is in combetween the blade and the side of the slot so that the sealing effect at this point is improved by the back pressure of the medium being compressed in the work chamber and this sealing effect, of course, increases with higher pressure.

In order to lubricate and assist in sealing the operating parts against the escape of the work.

medium, I provide an improved system wherein the piston is provided with internal chambers :93

opening laterally on the pistonsurfaces in contact with the end plates of the cylinder. The piston is also provided with ducts 95 communicating the chamber 93 block seats 85 thereof. The opposed side surfaces of the piston are also provided with annular grooves 91, which are connected together by ducts 99 extending through the piston. These ducts '99 in turn are connected to the piston bearing 6i and the internal chambers'93 by means of The piston is mounted so that the groove 91'- has a portion which at all times opens upon the bearing 39 and also upon a duct II3 formed in the wall of the housing I4. Means II5 comprising lubricant circulating apparatus, including a pump I II, for withdrawing the lubricant from the fluid forcing device, cooling the same, if desired, by means of a refrigerator IIB which may be included in the system I I5, and delivering the lubricant under pressure to the duct II3 from whence the lubricant is delivered to the cylinder bearing 39, the piston bearing 6|, the shaft bearing 29, and the seal device 3|. 1 The lubricant is also delivered into the chambers 93 and thence between the contacting end surfaces of the piston and end plates of' the cylinder and also into the groove 20 behind the bearing blocks in order to adequately lubricate the working surfaces and assist in sealing the pump. The lubricating and which it cooperates, 1 form v blocks 85 snugly therein. The bearing. blocks 85 have flat surfaces having sliding with the slot 20 in the bearingducts sealing medium may be returned to the circulating system I I through an outlet I I 9' from the seal 3 I The system I I5 may also be connected to deliver the sealing and lubricating medium under pressure through the opening H9 to the seal chamber from whenceit may flow into the piston and accomplish its. sealing and lubricating function,

' delivery pressure at which the. operating.

If the fluid forcing device is operated as a vacuum pump I am able to produce a degree of vacuum equal to 99.997%: of possible vacuum by maintaining apressure in the lubricating and sealing medium of 5 pounds above atmosphere,

being returned to the circulating system through the openingi I3. In either case, the housing may be provided with a sump SI to catch any Oil dripping from the cylinder, and return such oil to the circulating system. 3

A check valve I I1 is preferably included in the system II 5 in order to determine the pressure,

under which the lubricantis delivered in the fluid forcing device. The system II5, since it is connected with the sump 9|, is at the pressure prevailing within-the casing I 4 on the suction side 10f the lubricant forcing pump of the system II5 so that the lubricating and sealing medium will be delivered to the fluid forcing device at a pressure appreciably in excess of that in the housing I4. That is to say, in excess of the highest that is to say,/ with the barometer standing at 29.0625 millimeters of mercury I am able to produce in a single stage device embodying my present invention a vacuum of 29.05 millimeters of mercury. By decreasing the pressure in the lubrieating ands aling medium to 2 pounds, I am -able to obtain only 95% possible vacuum, and

pressure developed by the operation of the device I I. By adjusting the valve II! the sealing me-' dium may thus be delivered to the working parts of the fluid forcing. device, and more particularly between the end surfaces of the rotor and the engaging surfaces of the end plates at a pressure in excess of the maximum pressure developed in the work space.

I flnd it desirable to regulate the delivered prespossible vacuum is obtainable.

by decreasing the pressure to '1 pound, 94% of By supplying lubrication'only in the fluid forci device I am able to obtain a 93% vacuum which is approximately the vacuum which can be produced with the best; reciprocating vacuum pumps operating under ideal conditions.

It is thought that the-invention and numerous of its attendant advantages will be understood from the foregoing description and it is obvious that numerous changes may be made in the form,

construction, and arrangement of the several parts without departing from the spirit or scope of my invention or sacrificing'any of its attendant advantages, the forms herein described being premy invention.

sure of the sealing medium within limits which may be determined empirically and which apparently depend, at least to some extent, upon the size, capacity and construction of the fluid forcing device, and also upon the pressure or vacuum --conditions to be produced.

When the fluid forcing device is operated as a compressor, I find that pressure of IOQ pounds per square inch may be had at substantially maximum efficiency without pressure in the lubriferred' embodiments for the purposeof illustrating Having thus described my invention, 'what I claim as new and desire to secure by Letters Patent is as follows:

1. A pump or compressor comprising a frame and co-operating relatively movable elements ineluding a cylinder and a piston within the cylinder, said elements being mounted on the frame 7 with the axis of the cylinder eccentric with respect to the axis of the piston whereby said olements deflnea. work space therebetween, means eating medium, it being suflicient merely-to supply lubrication alone and to rely upon the accuracy and flt of the parts to prevent leakage of the work medium. Where pressures in excess of 100 pounds persq'uare inch are to be devoloped, however, I flnd it is necessary, in order to eliminate leakage of the work medium and consequent loss of operating efllciency in the fluid forcing device, to apply the lubricant as a sealing medium, in the manner heretofore described, under pressure while the exact pressure of the sealingmedium to produce operation at maximum efllciency is diflicult to determine I flnd that a pressure of approximately 5 pounds per square inch in ex-' cess of the maximum pressure of the work medium in the fluid forcing device is necessary where the device is operated to produce pressures of the order of 350 pounds per square inch, and I assume that pressures between 100 and 350 pounds at the discharge of the compressor will require corresponding excess lubricant pressures ranging between 1 and 5 pounds, and that pres-.

- within said casing with the axis of the cylinder on said cylinder for connecting the same -drlvingly with a source of power for rotating the cylinder about its axis, said cylinder having a wall opening in an end wall thereof and having a duct in the opposite end wall, said duct extending substantially radially in said end wall and opening axially on the inner surface of, said wall, said duct having outer portions in communication with said work space, said piston being carried on a shaft secured to the frame against all movement, 7 extending into the cylinder through said wall opening and having an end disposed opposite said axial duct opening, said shaft having a conduit in communication with said axial duct opening whereby a work medium delivered'in said work space may pass through said shaft channel and saidradial duct, and sealing means carried by the shaft and engaging the facing surface of the cylinder end wall around the'axial opening of the duct. V a

. 2. A pump or compressor comprising a high pressure casing and co-operating relatively movable elements including a cylinder and a piston within the cylinder, said elements being mounted eccentric with respect to the axis of the piston,

whereby said elements define a work spacetherebetween, means'on said cylinder for onnecting the same drivingly with a source of having a wallopening in an end wall thereof and having a duct in the opposite end wall, said duct extending substantially radially in said end wall compressor is wet for rotating the cylinder about its axis, said cylinder all movement, extending into the cylinder through said wall opening and. having an end disposed opposite said axialduct opening, said shaft having a conduit in communication with said axial duct opening whereby a low pressure work medium, delivered in said work space, may pass through said shaft channel and said radial duct, an annular seal carried by the shaft, yielding means urging said seal on the shaft to engage the, facing surface of the cylinder end wall around the axial opening of. the duct, said seal having a sealing flange externally exposed to the high pressure of the casing.

3. A pump or compressor comprising a frame,

relatively movable elements on said frame including a rotary cylinder, rotatable on its axis and 0 supported on said frame, and a, piston within the cylinder and rotatable on an axis eccentric with respect to that of the cylinder whereby to define a work space between the cylinder and the pistcnfi means to drivingly rotate said cylinder on its 5 axis, means on said cylinder for connecting the same drivingly with a source of power for rotating the cylinder about its axis, said cylinder comprising spaced end plates and an annular ring clampingly secured between said blade extending radially inwardly of said ring and engaging said end plates at its opposite edges and being clamped in place therebetween, said piston having a radial notch receiving said blade, the

, opposed sides of said notch forming seats, semiv wall of the cylinder, while the same is rotating,

cylindrical bearing blocks extending in the pockets of said notch between said end plates and engaging the opposed faces of said blade whereby to form a driving connection between said elements so that both may rotate together about, their relatively eccentric axes, said piston having an internal chamber opening on an end surface of the piston, means to deliver a lubricating medium at a pressure above the maximum work-space pressure into said chamber, through a wall of said cylinder while the same is rotating, from whence it may penetrate between the engaging end surfaces of the piston and cylinder to lubricate the same, and duct means in said piston communicating said chamber with said notch to supply lubricant freely from the chamber into the notch to lubricate the engaging surfaces of said bearing blocks, block seats, and blade.

4. A pump or compressor as set forth in claim 3, wherein one of said cylinder end plates "is .formed with an opening concentric with the axis of the cylinder and the frame comprises a sleevelike portion extending in said opening, bearing means in said openingfor journalling said end plate on said sleeve, the other end plate of the cylinder having a projecting shaft journalled in the frame and forming means whereby the cylinder may be drivingly rotated, said shaft having an axially extending lubricant duct communicat- 6 ing, through said other end plate, with the interior of the cylinder and with the lubricant chamber in the piston, said frame being formed with a lubricant duct communicating with said chamber, means connecting said shaft chamber and said frame duct in a lubricant circulating system, and means to circulate a lubricant under pressure through said system whereby to lubricate the operating parts of said fluid pressure 75 device.

end plates, a 30 said piston and. cylinder duct, said piston 5. Fluid forcing m ans comprising a rotary cminder and a pistonwithln the cylinder, said pis ton and cylinder having co-operating workin surfaces and being relatively movable to accomplish the fluid forcing function and defining a work space therebetween, means to deliver a sealing medium, through a wall of the cylinder; while the same isrotating, in position to penetrate between th co-operating working surfaces of the cylinder and piston at a pressure of the order of five pounds per square inch in excess of the maximum pressure in said work space during thev operation ofthe fluid forcing means whereby to prevent the escape of the work medium between said co-operating surfaces. j

6. A vacuum pump comprising a rotary cylinder and a piston within the cylinder, said piston and cylinder having co-operating working suri the same is rotating, in position to penetrate between the co-operating working surfaces of the cylinder'and piston at a pressure of the order of 'five pounds per square inch inexcess of atmospheric pressure.

'7. A compressor for the development of high pressures comprising a working stage embodying a rotarycylinder and a piston within the cylinder, having co-operating working surfaces and defining a working space and being relatively shiftable to accomplish compression of a work medium within said working space, means adjustable to deliver, through a in position to penetrate between the working surfaces of said piston and cylinder, a lubricating and sealing medium under pressure of substantially five pounds per square inch in excess of the maximum pressure developed within said work space, in order to seal against the escape of the work medium between the co-operating surfaces of the piston and cylinder.

8. A pump or compressor comprising a frame forming a gas-tight dome, cooperating fluid forcing members on said frame within said dome and including a rotatable cylinder, a piston within the cylinder and disposed in eccentric tang'entialrelation therewith, said cylinder including end plates secured at the opposite ends thereof and forming clearance spaces with the opposite ends of said piston, the circumferential surface of said piston defining a work space with said cylinder,

' partition means carried by and between said cylinder and piston in position dividing the work. space into intake and discharge stages, means for relatively moving said fluid forcing members to produce a fluid forcing action, and a lubricating and sealingsystem operatively associated with said fluid forcing members and comprising means forming a reservoir for a sealing fluid at the dis.- chargepressure prevailing in said dome, means to deliver a. fluid sealing medium from said 'reservoir in said clearance spaces at a pressure in excess of that prevailingwithin the dome, means for returning excess sealing medium to said reservoir, and meansoperabie outwardly of said dome to adjust the eccentric tangential relationship of said piston and cylinder. r

9. A pump or compressor comprising a frame forming a gas-tight dome, cooperating fluid forcing members on said frame within said dome and including a rotatable cylinder, a piston within the cylinder and disposed in eccentric tangential relation, said cylinder including end plates sewith the axis of the cylinder eccentric with recured at the opposite ends thereof and forming spect to the piston whereby said elements define clearance spaces with the opposite ends of said a work space therebetween, means for connecting piston, the circumferential surface of said piston one of the movable elements with a source of defining a work space with said cylinder, partipower for rotating the movable elements about etion means carried by and between said cylinder 1 their axes, said cylinder having a wall opening and piston in position dividing the work space, in an end wall thereof and having a duct in the into intake and discharge stages, means for relaopposite end wall, said duct extending substantively moving said fluid forcing members toprotially radially in said last-named end wall and ducev a fluid forcing action, and a lubricating and 10 opening axially on the inner surface of said lastsealing system operatively associated with said named wall, said duct having outer portions in fluid forcing members and comprising means communication with said work space, an axially forming a reservoir for a sealing fluid at the disimmovable shaft extending into the cylinder charge pressure prevailing in said dome, means through said wall opening and having an end to deliver a fluid sealing medium from said resdisposed opposite said axial duct opening, said ervoir in said clearance spaces at a pressure in piston being rotatably mounted on said shaft, and excess of that prevailing within the dome, means said shaft having a conduit in communication for returning excess sealing medium to said reswith said axial duct opening whereby a work ervoir, and means to cool the sealing medium as medium delivered in said work space may pass the same is delivered from the reservoir to said through said shaft and said radial duct, and clearance spaces.

resilient sealing means carried by the shaft and f A Pu p e s comp g a f me having a resilient sliding engagement with the and cooperating relatively movable elements infacing surface of the cylinder end wall around the eluding a cylinder and a piston within the cylinaxial duct opening. Y der, said elements being mounted on the frame 7 WILLIAM W. WISHART. 

